Electrical motors are widely used in the electrical appliances of people's life, and in manufacturing and production and various military equipment. An existing motor has a stator and a rotor, with a rotor shaft installed within the rotor and rotates with the rotor; as such, the motors output power. Because a rotor shaft of the an existing motor can only rotate with respect to the axis of the motor, the motor is called a planar motor for the reason that the movement of the rotor shaft has only one degree of freedom.
As shown in a prior art in FIG. 1, an existing motor may comprise a housing 10, and two end caps 11 and 12 at two ends of the housing 10. The housing 10 and the end caps 11 and 12 form a chamber. A stator 15 and a rotor 18 are provided in the chamber. The stator 15 comprises a stator core 16, and coils 17 wound on the stator core 16. The rotor 18 is provided within the stator 15, and may rotate with respect to the stator 15. A rotor shaft 19 is installed within the rotor 18, and through the interference fit with the rotor 18, the rotor shaft 19 is driven by the rotor 18 to rotate to output power.
A stator core 16 is generally formed by stacking multiple pieces of stator laminations of similar shapes. As shown in FIG. 2, a stator lamination 20 is formed by stamping a silicon steel plate material. The stator lamination is of an annular shape, and comprises a magnet yoke portion 21 at its outer periphery section. The magnet yoke portion 21 is of an annular shape. The stator lamination 20 also comprises multiple teeth 22 which project from the magnet yoke portion 21 outwardly from the center of the stator sheet along its radial direction. A winding slot forms between two adjacent teeth. A coil may be wound on a tooth 22.
As each stator lamination 20 is provided with a hollow center hole 24, the center holes 24 of the stator core 61 of the multiple stacked stator laminations form a rotor hole, to accommodate the rotor within.
The rotor core is formed by stacking multiple pieces of rotor laminations. A rotor core may be wound with coils of the rotor, or with aluminum molding. When a coil of the stator is energized, the AC current generates an alternating magnetic field in the coil 17 of the stator; the rotor 18 is driven by the magnetic field to rotate, which drives the rotor shaft 19 to rotate as well. Therefore, the stator 15 works as armature of the motor to receive electrical energy and to generate an alternating magnetic field.
However, many electrical appliances and industrial devices require components that may perform movement with multiple degrees of freedom. As an existing motor may move in only one degree of freedom, it cannot satisfy the application needs of the current electrical devices. Presently, multiple motors are used to perform movement with multiple degrees of freedom, which results in larger number of motors and a bigger volume in a device, and higher production cost.
Additionally, when one of the multiple motors breaks down, the whole device runs into a problem. Therefore such a device has poor stability. Furthermore, multiple motors require more precise control of the motors when working together, and place a very high requirement on the control of the equipment.